A Novel Compact High-Power X-Band Relativistic Magnetron With Diffraction Output

In a recent publication [IEEE Trans. Plasma Sci. vol. 53, no. 11, pp. 3285–95, Nov. 2025], we reported on the operation of a novel X-band relativistic diffraction output magnetron (MDO) producing over 100 MW microwave power at ~9.7 GHz with ~50% maximum electronic efficiency. Here, we present the results of the performance of an MDO with a significantly shorter diffraction output antenna (DOA), which makes the overall dimensions smaller by half. Guided by 3-D particle-in-cell (PIC) simulations, the experiments demonstrate that this MDO produces ~9.5 GHz high-power microwave (HPM) pulses reaching ~120 MW maximum power, ≤20 ns pulse duration, and maximum instantaneous electronic efficiency reaching ~100%. We also demonstrated that this relativistic magnetron (RM) operates well when four longitudinal slits were cut symmetrically in the vanes of the eight-cavity anode block, transforming it into a four azimuthally segmented MDO. This allows one to decrease drastically the duration requirements of the external magnetic field and, respectively, the energy stored in the magnetic field’s pulsed power supply. Finally, we present a novel design of a quarter-wave plate (QWP), which operates without breakdown at HPM powers exceeding 100 MW.